Field of the Invention
The present invention relates to a method of manufacturing a solar cell, and more particularly to a method of manufacturing a solar cell having a protective film formed over a semiconductor substrate or over a conductive area.
Description of the Related Art
Recently, due to depletion of existing energy resources, such as oil and coal, interest in alternative sources of energy to replace the existing energy resources is increasing. Most of all, solar cells are popular next generation cells to convert sunlight into electrical energy.
Solar cells may be manufactured by forming various layers and electrodes based on some design. The efficiency of solar cells may be determined by the design of the various layers and electrodes. In order for solar cells to be commercialized, the problem of low efficiency needs to be overcome, and thus, there is a demand to design the various layers and electrodes so as to maximize the efficiency of solar cells.
In one example, solar cells are provided with various protective films, in order to realize the passivation, physical protection, and electrical insulation of a semiconductor substrate or a semiconductor layer. These protective films may be formed by, for example, thermal oxidation or deposition. A protective film formed by thermal oxidation may make it difficult to precisely control the thickness thereof and to achieve excellent film properties. In addition, deposition is performed under an atmosphere including source gas, which contains elements for constituting a protective film, and, as needed, carrier gas. However, the protective film, formed using only basic gas, such as a source gas and carrier gas, may have a high interface trap density and may not provide good passivation for a semiconductor substrate or a semiconductor layer. Therefore, there is demand for a method of manufacturing a protective film having good properties.